Compact electric spring energized desktop stapler

ABSTRACT

A compact, electric, spring energized desktop stapler having a unitized housing providing both an external movable enclosure and a support frame for internal parts is disclosed. The internal power train is preferably elongated with the motor at the rear, a gear set toward the center, and low profile lever and power spring assembly at the front. The lever engages a striker with a normal upper rest position where the power spring is deflected and energized. A cam roller mounted to a final gear holds down the rear of the lever until the system is activated when the final gear rotates and the cam roller rolls off the end of the lever. In the unitized body, the base is pivotally attached to the body at the rear. A base lever selectively links to a cam roller or equivalent structure to move the body downward toward the base during a cycle.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority from U.S. Provisional Application No.61/675,648 filed Jul. 25, 2012, and from co-pending parent applicationSer. No. 13/943,644, filed Jul. 16, 2013, by the same inventor, thecontents of which are incorporated by reference.

FIELD OF THE INVENTION

The present invention relates to an electrically energized stapler, andin particular, a compact spring energized desktop electric stapler.

BACKGROUND

Power operated staplers are known in the form of pneumatic andelectrically powered devices. Such staplers are used for fastening inconstruction tools, and in the case of office type staplers, for bindingpapers. Powered office staplers are normally of the electric variety.Within the electric category common types are reduction gear driven by amotor, and impact driven through a solenoid. Gear driven types usuallyoperate relatively slowly through cam or lever means. The slow operationallows a low peak electric current, for example through battery power oran alternate source of DC power from a line powered low voltage adaptor.An impact system through solenoid operates quickly, but requires highpeak power, sometimes high enough to dim lights in an office setting.Further, the solenoid is expensive and bulky, including a large heavycopper winding. A further type of gear operated stapler uses the motorpower to store energy in a spring, whereby the spring drives a staple byimpact blow. However, these have required bulky structures.

In gear driven types, the amount of gear reduction required relates tothe available power of the motor and the stapling energy required. Afurther important variable is the efficiency of the design. In someknown prior designs there is substantial friction. Also in a designwithout spring energy storage the motor must drive through large changesin torque as the stapling cycle proceeds. As a minimum the gearreduction or motor size must allow for the peak forces of the cycle.This necessarily means the motor will operate well outside its peakefficiency loads or speeds for much of the cycle. A common such staplermay have four gear reduction stages to drive through such a cycle. Agear reduction device is also relatively slow typically requiring mostof a full cycle to complete before the fastener is ejected. Further, theslow action makes such designs ill suited for use in construction toolssince there is no anvil to press; the staple ejects too slowly topenetrate a wood or like surface.

In desktop use, pressing paper against or actuating a switch, orequivalent sensor, near the front of the stapler normally actuates thestapler. Commonly, the switch is to one side of the stapler. Thisfacilitates manufacture of the device but leads to a loss offunction—the actuation becomes sensitive to the angle in which papersare inserted. If the papers are angled toward the side with the switch,then the staple is installed too close to the edge of the page. If theangle is away from the switch, whereby the paper edge contacts an edgeof the device opposite the switch, there may be no staple operation atall since the papers are obstructed from moving against the switch. Theabove-described behavior is a source of familiar unpredictability ofoperating electric staplers.

Some electric staplers allow for moving the position of the switch tochange the location of the staple relative to the paper edge. Theconventional side mounted switch is a known method to provide anadjustable switch position since it is known how to fit it beside thestaple track in the various positions.

A common structure for an electric stapler includes an internal metalsupport frame and a separate external housing to form at least in part adouble walled construction. With the support and enclosure functionsseparate, the overall size necessarily is large. For example, it iscommon that the external housing remains stationary while the internalframe moves down toward the anvil during a cycle. This requires evermore bulk to provide such movable mountings. Such a structure is complexand expensive. The very large housing is necessarily plastic to keepcost and weight reasonable. But such a large plastic structure oftenfeels of low quality and amplifies noise.

SUMMARY OF THE INVENTION

The present invention provides improvements including size, efficiency,cost and usability to an electric stapler. In various preferredembodiments, it is of a gear motor type, with spring energy storage. Thesize in an exemplary 25 sheet capacity version is only slightly largerthan that of a conventional manual stapler. A unitized housing providesboth an external movable enclosure and a support frame for internalparts. The housing may be of either metal or plastic; if metal, such asdie cast, is selected the support frame will be sturdy, the externalsize will be especially compact and noise transmission is minimized Butplastic is a practical material also if desired. In either case thehousing also normally provides the external appearance of the device.

The power train is preferably elongated with the motor at the rear, agear set toward the center, and a low profile lever and an elongatedpower spring assembly at the front. The motor, gear set, lever and powerspring are all preferably at a same or similar vertical level, beingaligned in sequence along a length of the tool housing. Such alignmentpreferably includes the power spring and lever, with the power springbeing largely remote from the front of the tool. One or both of thepower spring and lever form a torque arm that is cantilevered from apivot axis to the front of the tool. With the structure as described,the tool can be compact vertically along its full length and further itcan be narrow in width at the front since there is minimal power springstructure at the front.

The lever engages a striker with a normal upper rest position. In thisrest position, the power spring is deflected and energized. A cam rollermounted to a final gear holds down the rear of the lever until thesystem is activated. Upon activation the final gear rotates and the camroller rolls off the end of the lever. The cam roller link is preferredover a non-rotating post since it will be of substantially greaterefficiency without the sliding action of a post. However, a wheel ismost useful when it is relatively large in diameter compared to a simplepost. But with a larger diameter wheel, the wheel may release the end ofthe lever slowly as it rolls off the rear most corner of the lever. Toreduce this effect, there may be a compliant link in the gear train toallow limited back motion between gear elements.

In accordance with a preferred embodiment unitized body, the base ispivotally attached to the body at the rear in a desktop configuration.This is consistent with a compact device that is minimally larger than afamiliar desktop stapler. A base lever selectively links to a cam rolleror equivalent structure to move the body downward toward the base duringa cycle. There is no need for a stationary external shell althoughstationary elements may be included if desired.

In a preferred embodiment, the power spring is a double torsion typewith arms extending forward from a common mounting. Optionally, anelongated wire or flat spring may be used. With the elongated spring,the spring structure, the lever and the power spring both extendrearward from the striker. They both remain substantially behind thestriker so that the front end of the stapler can be preferably no largerthan required to fit the striker, with respect to a front view.

The stapler of the present invention preferably includes an adjustablesensor switch. This sensor is activated upon contact or sense of a paperedge. The sensor is positioned at or near the center of the staplerbody, with respect to a front view, just below the staple track. Beingon center removes dependency on the angle of the paper. In contrast, forexample, a conventional right side mounted sensor will trigger early ifthe paper is inserted with an angle further in on the right side. Withthe on center sensor, the stapling operation is closer to a user'sexpectations.

Along with the center mounted sensor the present invention preferablyincludes an adjustable sensor position along a length of the body. Thisallows a range of positions for a staple from the paper edge. Apreferred embodiment sensor structure translates along the body andcommunicates with an elongated sensor bar in the body. Pressing anywhereby the sensor structure along the length of the bar actuates anelectrical switch within the body. Therefore, the switch can be fixed inthe body so that the connecting wires do not need to flex as in otheradjustable switches. An adjusting wheel, rather than a detent slide, forexample, moves the sensor for improved control of the sensor position.

In a preferred embodiment, the internal parts of the body all mount intoone side. In this way there are no wires or connectors and minimal linksto cross to the opposed side. This simplifies assembly and improvesreliability.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a top, front, left side perspective view of a preferredembodiment electric stapler according to the present invention.

FIG. 2 is the stapler of FIG. 1 with a left housing omitted to exposeinternal components.

FIG. 3 is a right side elevation view of the electric stapler with theright housing omitted.

FIG. 4 is an exploded view of the components of the electric stapler.

FIG. 5 is a top, right side perspective view of the electric staplerwith the right housing omitted to show a rest condition of thecomponents.

FIG. 5A is a power spring in an energized rest condition correspondingto its position in FIG. 5.

FIG. 6 is the stapler of FIG. 5 in a condition immediately after releaseof the striker to eject a staple.

FIG. 6A is the power spring in a released and preloaded conditioncorresponding to its position in FIG. 6.

FIG. 6B is a detail view of the stapler toward the right housing showingan offset gear axle.

FIG. 7 is the stapler of FIG. 5 in a pre-energized condition.

FIG. 8 is a top, left side perspective view of the stapler.

FIG. 9 is a front elevation view of the stapler.

FIG. 10 is a cross-sectional view of FIG. 9 taken along line 10-10 withthe stapler in the pre-energized condition of FIG. 7.

FIG. 11A is a detail view from FIG. 10 showing the paper sensor in anormal position.

FIG. 11B is the view of FIG. 11A with the paper sensor in a pressedposition.

FIG. 12A is a top perspective view of a paper sensor subassembly in thenormal position of FIG. 11A.

FIG. 12B is the view of FIG. 12A with the paper sensor in the pressedposition.

FIG. 13 is a reduced size view of FIG. 3 for cross-reference with FIGS.13A and 13B.

FIG. 13A is a cross-sectional view of the stapler of FIG. 13 taken alongline 13A-13A, viewed from the front, showing the paper sensor in thenormal position, with the housings omitted.

FIG. 13B is a cropped, cross-sectional view of the stapler of FIG. 13taken along line 13B-13B, showing the paper sensor in the pressedposition, with one housing half omitted.

FIG. 14 is a detail view of FIG. 3 with the paper sensor subassemblyadjusted to a rearward position.

FIG. 15 is a bottom view of the stapler of FIG. 14 showing sensorposition adjusting elements.

FIG. 16 is a bottom perspective view of a depth pointer.

FIG. 17A is a perspective view of a gear and clutch subassembly in adrive condition.

FIG. 17B is the same view as FIG. 17A, but with the clutch in apost-release condition.

FIG. 18 is an internal side elevation view of a left housing of thestapler.

FIG. 19 is a detail view of an attachment of a base to the body of thestapler.

FIG. 20 is a cross-sectional view of FIG. 19 taken along line 20-20showing a base stop limit rib.

FIGS. 21A-D are electrical schematic views of switch states for anoperating cycle.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention is directed to a compact, spring-energized,electric stapler shown in the preferred embodiment of FIG. 1. FIG. 4provides an exploded view of the major internal components of thestapler shown in FIG. 1.

FIG. 5 shows some of the components of the preferred embodiment electricstapler of the present invention. Power spring 90 is in a deflected restposition as seen in the isolated view of FIG. 5A. Gear wheel 83 links torear end 64 of lever 60 at the lower cam roller 83a. In the illustratedembodiment, there are two identical opposed gear wheels 83 to reduce thenumber of unique parts. However, the detailed features are fully usedonly in the left side gear, the gear shown for example in FIGS. 5 and 6.The right side gear provides support for axles (not shown) for camrollers 83a, and optionally as a second mating gear for gear 82a. If theaxles are of sufficient strength the right side gear may be omitted.

Gear wheel 83, or the first gear, is stationary in the normal restcondition of FIGS. 2, 3 and 5 whereby the power spring 90 is deflectedand energized before a firing cycle. Ratchet detent 83b is movablyattached to housing 10 to selectively engage catch rib 83f of gear wheel83 (FIG. 8) to prevent backward rotation of the gear wheel from the restposition. Rib 83f of gear 83 is shown as a termination of a recess in aface of the gear. There are preferably two such recesses in the gearface, FIG. 4. Ratchet detent 83b remains proximate to rib 83f within therecess so that gear wheel 83 cannot reverse, counterclockwise in FIG. 5.Ramp 83d of the recess in gear wheel 83, FIGS. 4 and 8, allows detent83b to ride smoothly out of the recess when gear wheel 83 turns in itsnormal direction.

Gear 83 or other linked element should be stopped in a consistent restorientation without over spinning to an unstable toggle position thatcauses unintentional firing. This unstable condition is also discussedbelow in the context of gear link 82. As seen in FIGS. 3 and 5, roller83a presses lever end 64 at an angle before its perpendicularrelationship to the lever end, the toggle position. The two smallcircles on gear 83 correspond to the roller positions, while the rollersare not directly shown in FIG. 3. Described another way gear 83 rotatesuntil roller 83a causes lever 60 to pivot near to but not entirely atits corresponding highest striker position. In this position, the forcefrom power spring 90 causes a reverse rotational bias acting on gear 83,counterclockwise in the view of FIG. 3. Therefore, the electric motorcontrollers, discussed below, stop gear 83 sufficiently before thetoggle position to ensure the gear does not over spin and cause firingof striker 100. Accordingly, the rotational position of detent 83b ongear 83, or equivalent structure, is such that lever 60 holds striker100 near but not at its upper most possible position. The reverse biason gear 83 against detent 83 then holds the assembly stable in the restcondition. Gear 83 may rotate in reverse slightly from the stop positionto its rest orientation against the detent. It is then a short portionof the operating cycle to move the gear to the toggle and then releaseposition. Preferably, there are two detent positions on gear 83 orequivalent structure as shown. Since gear 83 rotates one half turn percycle each such detent corresponds to a single predetermined verticalposition of striker 100 in each operating cycle. Optionally, more thantwo detents may be included.

As an operating cycle begins, gear wheel 83 turns clockwise in FIG. 5and cam roller 83a rolls off rear edge 64 of lever 60. The lever 60 isfree to move and energized power spring 90 forces or urges striker 100downward to eject a staple (not shown) from track 70 by impact blow.Staple pusher 400 biases the staples or like fasteners to move towardstriker 100. Pusher bar 71, FIG. 13A, supports a compression spring (notshown) that provides the spring bias to move pusher 400. Tabs 62 oflever 60 normally contact absorber 220 in the striker lowest position.Nosepiece 300 provides a front terminus to the track 70 and a guidechannel for staples and striker 100.

Cam roller 83a is of sufficiently large diameter to usefully roll abouta small axle (not shown) fitted to gear wheel 83. Alternatively, a postor sharp-edged hard rib of gear wheel 83 may be used to engage the rearof the lever 60. But using a roller provides substantially reducedfriction between gear wheel 83 and lever 60. In using a relatively largecam roller, it will tend to roll off of lever end 64 slowly until thetwo are separated. After separation, the normal energy release andstriker motion occur. But during separation there can be lostperformance since lever 60 will be released slowly during the roll-offprocess. An analogy is a car tire rolling slowly off a curb. If the tireis reasonably large in diameter, the car can move downward slowlywithout damage. But in the case of a power spring, it is desirable tocause damage in the form of holes in the paper being stapled. If a smallpart of the lever motion is gradual, some of the potential energy in thespring is not available for impact action.

To provide a low friction roller but maintain a sudden release, therecan be free play or a compliant link in the system. Then the cam rollerscan “flick” away from lever end 64. For example, the cam rollers may beloosely or slidably mounted to gear wheel 83. In the preferredembodiment, the free play is in the mated gear subassembly of FIGS. 17Aand 17B. Gear link 82 includes gear 82a and stop ribs 82b, fitted into arecess of second gear 81. In the normal drive condition, second gear 81rotates counterclockwise. Stop ribs 82b press recess ribs 81b of gear81. Second gear 81 can thus drive gear 82a. This position of thesubassembly is normally maintained in the rest condition of FIG. 5 aswell as the moving drive condition. As cam roller 83a moves toward thelever distal end at 64 it becomes unstable. The action briefly reversesso that gear wheel 83 briefly drives gear 82a. Gear link 82 can freelymove a predetermined angle within second gear 81. Forces within the gearsubassembly of FIG. 17A then reverse to cause this angular motion to theposition of FIG. 17B. Second gear 81 does not make any sudden motion,but inner gear link 82 and gear wheel 83 both move suddenly with gearwheel 83 moving clockwise to about the position of FIG. 6. In effect,cam gear 83 briefly overshoots the gear train driven by motor 200. Theresult of the above interaction is cam roller 83a does its roll-offinstantly. Optional stop ribs 82b may be resilient extensions as shown,or equivalent absorbing structures in the gear subassembly, to cushionany impact of the sudden reversing motion. In an alternative embodimentroller design, a post or rib of gear wheel 83 may engage a roller fittedat end 64 of lever 60. The compliant link retains the same advantage.

Next, back in the gear train is third gear assembly 84 and 84a. Fourthgear 80 mates to motor 200 on shaft 200a. The gears are preferably madefrom molded plastic such as acetal or nylon. Other materials may also beused such as other plastics, ceramic, steel, die cast zinc, or machinecut bronze, or any combination thereof. In the preferred embodiment,there are three gear reduction stages for a reduction ratio of betweenabout 100 to 120, including both outer limits and all valuestherebetween. In contrast, a conventional direct drive device withhigher friction and large torque variations may require a ratio of over150 to allow a practical size and motor. Using spring energy storagekeeps the required motor torque relatively constant since the motor isused to deflect a spring rather than directly drive a staple. The motorcan then operate near its peak efficiency through most of a cycle.

Power spring 90 includes upper loop 94 and lower arms 92. At the end ofthe lower arms is bent tip 91, FIGS. 5A, 6A. FIG. 5A corresponds to therest condition of the stapler where the spring is deflected andenergized. In FIG. 6A the spring is non-deflected in a preloadedcondition. Arm tips 91 extend within loop 94 to hold the preloadedcondition stable. By holding a deflected rest condition the stapler isprepared to operate immediately upon activation. There is no need towait for wind up or cycling through an operation. Rib 15, FIGS. 14 and18, holds lower spring arm 92 against upward forces so that spring arm92 remains substantially stationary in the housing.

Spring loop 94 fits to slot 63 of lever 60, FIG. 14. Lever tip 61extends through opening 101 of striker 100, FIG. 8. Therefore, thestriker and the lever move along with spring loop 94. The striker isheld loosely on the lever tip as the striker moves up when spring 90 isenergized, being gently guided by channel 11, FIG. 18. As a result thereis minimal friction in a re-set energizing stroke as lever 60 liftsstriker 100 against the downward bias from power spring 90.Alternatively, the lever and spring can engage the striker at separatelocations of the striker. But then there will be sliding friction underforce as the spring and lever oppose each other on the striker and arein and out of striker openings.

As seen in the drawing figures, lever 60 is elongated rearward fromstriker 100. Lever 60 pivots about a side to side or lateral axis,preferably but not necessarily at an axis concentric with a coil ofpower spring 90. In FIG. 3, the pivot axis goes into the page. Suchorientation allows lever 60 to be elongated with minimal sliding at itsarcuate engagement to striker 100. In FIG. 3, it is seen that the pivotaxis is vertically coincident or aligned with gear 83 or other gears ofthe gear set. As discussed above, the lever 60 is preferably biased bypower spring 90 or other type of spring. The lever 60 in turn drivesstriker 100. According to this structure as illustrated in the drawingfigures, lever 60 has a spring energized torque applied to impart avertical downward bias on striker 100. The torque is generated orapplied substantially from rearward of the striker, at the coil of thepower spring in the illustrated embodiment. The lever, spring, or springthrough the lever, is cantilevered toward the striker to convert thetorque to a downward force on the striker. More generally, striker 100is driven downward in majority by a torque arm, in contrast to directapplication of compressive or extensive spring force immediately at thestriker location. The torque arm is the lever 60 or may include afurther component, such as the power spring 90, near to the lever. Inthe example earlier, with the power spring directly engaging thestriker, such engagement preferably remains nearest to or substantiallyvertically coincident with the lever at the striker location to maintainthe vertically compact features of the preferred embodiment.Alternatively, the torque may be applied to the lever through thecantilever by an extension or compression spring linked to the lever andlocated rearward of the striker, or through a flat spring.

Housing 10 is compact at the front where the lever front end is adjacentto an interior ceiling of the housing in the rest condition, as seen inFIG. 3. The striker 100 is just tall enough to provide opening 101 toreceive lever tip 61 for actuating the striker acceleration to eject astaple, yet still fitting within the compact front of housing 10. Withthe torque arm positioned as illustrated in the drawing figures betweenthe motor and the striker, with all being at a similar verticalposition, the operating elements are elongated and compact bothvertically and laterally.

In a paper fastening type stapler, as a staple is ejected, the stapleexit end must be pressed toward the base as in FIG. 6. In a conventionalelectric stapler, the base and body are a single unit where the stapleexit end moves downward internally within a housing. In the preferredembodiment of the present invention, the body and base motion areexternal. The body is a unitized construction with a single housing 10and 10a providing both an exterior shell and the internal frame tosupport the working parts. The base 20 is preferably a discrete orseparate element pivoted to the housing 10 and moves independently,separately from the housing. The preferred embodiment base 20 issubstantially exposed outside the housing 10, 10a at least about thebase sides, top and bottom near a front portion of the base. Asillustrated, about half the base 20 is so exposed. This constructionallows the design to be compact since the main structures are all singlewalled, i.e., without an internal frame or nested base. Base 20 includesfoot 20a. A rear foot 10a is attached to housing 10 and moves with thehousing.

According to the preceding discussion, base 20 includes pivot post 22 tofit recess 12 of housing 10, FIGS. 18 and 19. Base link 50 is attachedto base 20, discussed in further detail below. Pressing upward at cam 51of link 50 causes base 20 to move toward housing 10. Base 20 cantherefore close against the paper sheets to be stapled (not shown). InFIG. 5, one of the cam rollers 83a is positioned next to cam 51 but hasnot yet pressed it. Base 20 remains in its rest position spaced fromhousing 10. As gear wheel 83 rotates clockwise from FIG. 5 toward andincluding its position in FIG. 6, cam roller 83a forces link cam 51upward. In FIG. 6 it is seen that housing 10 is moved against base 20.This action corresponds to just before and after the roll-off of lowercam roller 83a that leads to ejecting a staple.

Normally there are papers (not shown) situated between the housing andbase. In FIG. 6, the stack height would be zero since the base 20 andhousing 10 are in contact. In fact, the stack height may be, forexample, 0.10 inch for 25 sheets of typical paper. To allow for thisheight, link 50 is able to move relative to base 20 to avoid excessforce on a rigid structure. Base link 50, FIG. 10, is pivotally mountedto base 20 at recess 53. Base spring 195 pulls the link at opening 52 sothat edge 57 normally contacts a rearward face of base 20. Base spring195 attaches at front end 196 to the base. Base link 50 and base 20therefore can pivot together on housing 10 about pivot 22. But whenthere is an obstruction, such as a paper stack, base 20 can stop movingtoward the housing and link 50 can continue to rotate counterclockwisein FIG. 10 under the force from cam roller 83a. The configuration ofFIG. 10 would not actually cause the base to move since it shows acondition after a stapling operation just before the spring isenergized. However, FIG. 10 shows a clear view of base link 50. FIG. 6shows the closed base position, so if there were an obstruction to thebase motion toward the closed position, there would be a space in frontof link edge 57, as seen in FIG. 10, as link 50 rotates relative to theno-longer-moving base.

To provide an upper limit stop for housing 10 moving away from base 20,rib 11 of housing 10 selectively engages rib 23 of base 20, as seen inFIGS. 4, 18, 19 and 20. Base bias spring 190 holds the housing spaced anormal distance above the base by pressing upward at front end 191.

To remedy a jam, it can be useful to pull the base 20 open beyond itsnormal distance. For example, a malformed staple leg may get stuck inanvil 56, especially when stapling thick paper stacks. An optionalfeature of the present invention allows that the housing-base openingcan be temporarily increased. Accordingly, recess 12 preferably is aslightly vertically elongated opening, FIG. 18, whereby post 22 ismovable vertically within the recess. Normally, rear end 192 of the biasspring presses upward on rib 14 of housing 10 to hold post 22 pivotallyat a bottom of recess 12. If base 20 is forcibly opened from its normalposition, base rib 23 pivots slightly about a fulcrum of housing rib 11.Post 22 moves upward (not shown) in elongated recess 12 whereby thefront of the base 20 moves away from the housing 10. Rib 24 of the base20, FIG. 4, limits the position of spring rear end 192 to a preloadedcondition in base 20.

The present invention in various preferred embodiments furthercontemplates improvements to a paper sensing system. A preferredembodiment sensor subassembly is shown in FIGS. 12A and 12B. Adjustingslide 47 is movable in a channel or equivalent structure along a lengthof housing 10. See also FIGS. 11A, 11B, 13A, and 13B. Sensor button 40moves within slide 47 between a normal position (FIG. 12A) and a pressedposition. These button positions are operable for any position of slide47 along housing 10. In FIGS. 11A and 11B, slide 47 is in a forward mostposition. This corresponds to installing a staple closest to an edge ofthe paper. Sensor wire 46 is pivotally mounted to slide 47 at pivot 47a,and at a bottom to button 40 at recess 41, FIGS. 11A, B. The button isloosely held at its front within slide 47. Button 40 thereby moveseasily within slide 47. The button 40 and supporting slide 47 areimmediately adjacent and below track 70 rather than the conventionalposition of a switch beside the track. In the normal position, wire 46is substantially vertical with end 46a being horizontal, FIG. 11A. Asbutton 40 is pressed at button front 42, wire end 46a rotates upward,FIG. 11B. Sensor flap 45 is pivotally mounted to housing 10 at pivot45a, FIG. 4. Wire end 46a causes flap 45 to rotate upward, FIG. 13B.Flap 45 selectively engages contact 201a of switch 201 to trip switch201. See also FIG. 7 for the relative positions of flat 45 and contact201a.

FIG. 14 shows a rearward position of slide 47. This corresponds toinstalling a staple farther from an edge of the page. The relationshipbetween slide 47 and each of button 40, sensor wire 46, and flap 45remains functionally unchanged for any selected slide position. Pressingpaper against button front 42 creates the same result as for the forwardslide position of FIG. 10. Specifically, pressing the button causes flap45 and contact 201a to move as described above. With this structure thusdescribed a paper sensor is on-center in the stapler and is alsoadjustable for depth.

Adjusting slide 47 may be directly moved within housing 10 to select astapling position. For example, a tab of slide 47 may extend externallyfrom a side of housing 10 (not shown) to allow a user to move the slide.In the preferred embodiment, depth pointer 43 surrounds or links toslide 47 whereby moving pointer 43 causes slide 47 to move. Thesecomponents are visible together in FIG. 7 where the track and relatedcomponents are removed for clarity. Also see FIG. 4 where slide 47 isdirectly above its operative position nested within pointer 43. Slide 47can slide along housing 10 but is largely fixed lengthwise in pointer43. Pointer 43 is slidable along the length of base 20 while slide 47can move vertically in pointer 43 as base 20 moves to and away fromhousing 10. So slide 47 is slidably fixed to housing 10 while pointer 43is slidably fixed to base 20. As pointer 43 is moved, it contacts slide47 to cause the slide to move. As housing 10 pivots toward base 20,slide 47 moves downward into pointer 43. Pointer 43 includes itsnamesake indicator 44 to show where the paper edge will be when thestapler is activated.

As with slide 47, pointer 43 may be directly moved along the base bypushing at or near indicator 44 or other location. This may compromisethe appearance and be difficult to control. Further, it can createasymmetric binding forces on the pointer unless the pointer is pushedfrom both sides. Although the above compromises do not preclude thoseoptions in the preferred embodiment, adjusting wheel 120 links topointer 43 to allow moving the pointer. As seen in FIGS. 15 and 16,adjusting wheel 120 links to gear rack 48 of pointer 43 through gear121. Retaining plate 122 holds the gear assembly in place in base 20.Adjusting wheel 120, or a linked component, preferably includes detentrecesses or equivalent structures to engage base 20. For example, fourrecesses in a top face of adjusting wheel 120 can be seen in FIG. 4.Such detents provide tactile feedback to a user and hold a position forslide 47. Retaining plate 122 is flexible to provide some resilientvertical motion of the adjusting wheel to allow effective function ofthe detent action. A resilient detent may engage this system in otherplaces or directions, for example, upon a side of pointer 43. By using awheel with detents it is easy to accurately adjust the sensor position.

Pointer 43 is biased lengthwise by gear 121 relatively near a centerlineof the stapler. This limits twisting and binding forces on pointer43—such forces being in rotation with respect to the view of FIG. 16. Incontrast, a tab of pointer 43 extending, for example, to the lowestposition of adjusting wheel 120 in FIG. 16 would tend to twist and bindpointer 43 in its track on base 20. Optionally, an exposed sliding tabon base 20 is separate from pointer 43 to engage pointer 43; this wouldalso reduce the torque arm on pointer 43 that causes binding.

Normally the sensor system is biased toward the normal positions ofFIGS. 11A and 13A, with respect to the sensor flap, wire and button. Thebias results from the spring force of contact 201a of switch 201 and theweight of flap 45. In the case that an obstruction or other abnormalevent occurs, ratchet detent 83b discussed earlier preferably includes afurther function to ensure re-set of the sensor system. Sensor flap 45has a tab 45b, FIGS. 4 and 8. An extension of detent 83b selectivelypresses tab 45b as gear wheel 83 turns. Specifically, ramp 83d of thegear wheel drives ratchet detent 83b away from the gear wheel. Tab 45bis forced to move to rotate sensor flap 45 to its lowered rest positionof FIG. 13A. In turn, sensor wire 46 and button 40 are forced or atleast firmly biased to move to the normal positions shown in FIG. 11A.This back up system prevents improper continuous cycling in the event ofsensor jams. But as noted previously, flap 45 with tab 45b is normallymoved instead from the switch return bias and weight forces.

For control of the operating cycle, a second switch 202 (FIG. 8) isfitted. Gear wheel 83 includes cam track 83e. Switch link 83c movesaccording to the profile of cam track 83e of gear wheel 83, which inturn corresponds to the cycle positions of cam rollers 83a and lever 60.Switches 201 and 202 may be single pole double throw types. FIGS. 21A toD show switch states for switches 201 and 202 through the operatingcycle. According to the function described, the stapler operatesprimarily or entirely by electromechanical switching without a need forelectronic circuits, microprocessors, or components. This reducesmanufacturing cost, component expense, and improves reliability.However, such components may be included if it is appropriate.

FIG. 21A shows the rest state. This corresponds to the condition in FIG.5. Motor 200 is isolated from power. FIG. 21B is the rest condition butwith button 40 pressed by paper sheets to trip switch 201 and close thecircuit to motor 200. FIG. 21C is the released condition of FIG. 6. Thepaper is still in place immediately after ejecting the staple. Cam track83e has rotated to a position to trip switch 202 to open the circuit andstop the gear motions. In FIG. 21D the user has removed the paper.Switch 201 moves to its normal position closing the circuit until camtrack 83e advances to the original rest position to open switch 202 andstop the motion.

The switches are shown as mechanical contact type. Optionally, they maybe in the form of proximity type, for example, magnetic or optical.Electric socket 205 is fitted tightly within housing 10.

Most of the gears and rollers preferably rotate upon simple posts oraxles (not shown). For second gear 81, axle 84b may include an offsetend as seen in FIGS. 6 and 6B. A straight axle would require a smallerdiameter third gear 84 to clear the axle, reducing the available gearreduction. With the offset, axle 84b goes around third gear 84. Theoffset portion fits into slot 11a of housing 10a to stabilize the axlein the vertical direction, while the end fits into a round recess withinthe slot to hold the horizontal direction. The assembly of gears 84 and84a extends substantially across the width of the body of the staplerwith the respective gears at opposed ends. This provides clearance forvarious components and allows room for the offset of axle 84b.

Track 70 extends forward (not shown) to load staples. To extend thetrack release 110 is pressed forward by release button 112. Tip 114presses the track release to rotate the track release and free thetrack. Release button 112 preferably includes integrated spring tabs 113to hold the button in its normal rearward position in housing 10.Release button 112 preferably includes a relieved upper face to clearmotor 200, visible in FIGS. 4 and 8.

In the disclosure there are references to housing 10. Where applicablethis more generally refers to the body comprising housing halves 10 and10a.

While particular forms of the invention have been illustrated anddescribed, it will be apparent that various modifications can be madewithout departing from the spirit and scope of the invention.Furthermore, it is contemplated that features of one embodiment may becombined or used in another embodiment.

What is claimed is:
 1. A compact, motorized fastening tool, comprising:a body including a front, rear, top, bottom and sides; a fastener guidetrack extending along the bottom of the body; a striker at the front ofthe body including an upper striker position above the track and a lowerstriker position in front of the track; a base pivotally attached to therear of the body, the base extending forward under the body from thepivotal attachment to the front of the body; a gear set disposed along alength of the body above the base, the gear set including a motor andgears linked thereto, the gear set supported within the body with gearset supports being substantially fixed in position on the body inrelation to the fastener guide track through a normal operating cycle;the body including an upper rest position with the front of the bodyspaced above a front of the base, and a closed base position of the bodywherein the body is rotated downward toward the base; a base linkselectively engaging the gear set at a base link first end, the firstend being within the body, a second end of the base link engaging thebase; and the gear set including at least the motor thereof, the body,and the guide track all pivoting together in relation to the base toreach the closed base position.
 2. The motorized fastening tool of claim1, wherein the base is discrete and separate from the body andsubstantially exposed to move outside the body.
 3. The motorizedfastening tool of claim 1, wherein a the top of the body is largelyexternally exposed, and to assume the closed base position, the exposedbody top moves downward toward the base.
 4. The motorized fastening toolof claim 3, wherein the body comprises both of an outermost shell and aninternal support frame, and wherein the outermost shell with theinternal support frame move downward toward the base.
 5. The motorizedfastening tool of claim 1, wherein the base link partly surrounds thegear set within the body, and an upper arm of the base link extends tothe first end above the gear set and a rear arm of the base link extendsdownward to the second end rearward of the gear set.
 6. The motorizedfastening tool of claim 5, wherein the rear arm passes rearward of thefastener guide track.
 7. The motorized fastening tool of claim 1,wherein the base link includes a resilient connection between the bodyand the base wherein the body can be normally, forcibly moved away fromthe base by deflection of the resilient connection.
 8. The motorizedfastening tool of claim 1, wherein a final gear of the gear set includescam features, and the cam features selectively engage the base linkfirst end.
 9. The motorized fastening tool of claim 8, wherein the camfeatures engage both the base link first end and a striker actuationlever wherein a timing of striker motion and body-to-base motion iscoordinated.
 10. The motorized fastening tool of claim 9, wherein thecam features include rollers fitted to the final gear.
 11. The motorizedfastening tool of claim 10, wherein the final gear includes twoattached, diametrically opposed rollers, and at a predeterminedrotational position of the final gear, a first roller presses the baselink first end to pivot the body on the base and a second rolleractuates the striker to move within the body.
 12. A compact, motorizedfastening tool, comprising: a body with a front, rear, top, bottom, andsides; a fastener guide track disposed along the bottom of the body; astriker disposed at the front of the body including an upper strikerposition above the track and a lower striker position in front of thetrack; a motor supported on the body toward the rear of the body; a gearset engaging the motor, the gear set mounted and supported by the body;a pivotal attachment of the base to the to the rear of the body, thebase extending forward under the body from the pivotal attachment to thefront of the body; and the base and body having separately movableexternal structures of the fastening tool wherein each of the motor, thegear set, and the body moves in the same manner together about thepivotal attachment toward the base during a normal operating cycle. 13.The motorized fastening tool of claim 12, wherein the body is a unitizedbody that provides both an external shell enclosure and a support framefor internal parts including internal structures to guide and supportthe gear set and motor, the internal parts moving together with theexternal body shell toward the base about the pivotal attachment duringthe normal operating cycle.
 14. The motorized fastening tool of claim12, wherein the body along with the striker is driven toward the baseduring the normal operating cycle, and with the body held in a closestposition against the base, the striker is pushed downward in a channelof the body toward the base.
 15. The motorized fastening tool of claim13, wherein the guide track normally remains fixed in position on thebody through a full operational cycle.
 16. The motorized fastening toolof claim 12, wherein a base link selectively links the body to the baseto cause the body to move toward the base, and a final gear of the gearset includes two attached, diametrically opposed cam rollers, and at apredetermined rotational position of the final gear, a first rollerpresses a base link first end and a second roller actuates the strikerto move within the body.
 17. The motorized fastening tool of claim 16,wherein the base link includes an upper arm extending to the base linkfirst end over the gear set and motor, a rear arm extends downwardbehind the gear set, and the base link includes a resilient connectionto the base wherein the base, in its position nearest the body, isnormally forcible away from the body by deflection of the resilientconnection.
 18. The motorized fastening tool of claim 17, wherein therear arm extends downward behind the guide track.
 19. The motorizedfastening tool of claim 12, wherein the base is substantially entirelyexternally exposed at a front portion, and the body normally movesdownward toward the exposed front portion, and the base liessubstantially entirely below the guide track.
 20. A spring assembly of afastening tool, comprising: a housing with a front, rear, top, bottomand sides; a fastener guide track along the bottom of the housing; astriker at the front of the housing including an upper striker positionabove the track and a lower striker position in front of the track; alever and power spring disposed at a front of the housing, wherein thelever is elongated rearward along a length of the housing, the powerspring being a torsion type acting on the striker in majority through atorsional connection to cause a downward bias on the striker; the powerspring including a first spring end movable with respect to the housing,the first spring end linked to the striker to move with the striker, asecond spring end, and a structure of the power spring disposed betweenthe first and second spring ends extending substantially behind thestriker; the power spring being elongated including a first armextending forward from a coil of the power spring to the first springend adjacent to the striker, a second arm of the power spring extendsfrom the coil to the second spring end; the first spring arm being abovethe second arm in a deflected energized condition of the tool, and thespring is not deflected in a released condition of the tool wherein thefirst arm is moved down to be adjacent to the second arm; and the secondspring arm including a segment angled with respect to the first springarm wherein the angled segment passes under the first spring arm, theangled segment being adjacent to the first spring arm whereby the springis preloaded in the released condition, and the angled segment beingmoved away from the first arm under a bias from the lever in thedeflected energized condition.
 21. The spring assembly of claim 20,wherein the first spring arm is below the second spring arm adjacent tothe coil, and the first spring arm passes beside the second spring armto be above the second spring arm at distal portions of the arms furtheraway from the coil.
 22. The spring assembly of claim 20, wherein thesecond spring end includes a vertically extending portion adjacent tothe first spring arm, the vertically extending portion passing besidethe first spring arm to extend upward from below the first spring arm inthe released condition of the tool.
 23. The spring assembly of claim 22,wherein the second spring end includes a bent tip, and the tip includesthe vertically extending portion.
 24. The spring assembly of claim 20,wherein the first spring arm directly engages the striker.